Visible light photocatalytic activities of ZnFe2O4/ZnO nanoparticles for the degradation of organic pollutants

•Co-precipitation method is proposed to synthesize magnetic nanoparticles.•Modifications in the molar concentration lead to the shift in absorption edge.•Superparamagnetic property is demonstrated for the nanoparticles.•Two dye pollutants are utilized to demonstrate the photocatalytic activity.

ZnFe2O4/ZnO nanoparticles have been synthesized by co-precipitation method using polyvinyl alcohol (PVA) as surfactant. The phase formation of synthesized products was systematically investigated from powder X-ray diffraction. Cubic ZnFe2O4 and hexagonal ZnO were identified in accordance with different molar concentrations of Fe3+ ions. The morphology and functionality were analyzed using field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and Fourier transform infrared (FTIR) spectroscopy. The optical properties and change in the band gap from UV to visible region upon increasing molar concentration of Fe3+ ions were analyzed from diffuse reflectance spectra (DRS). Superparamagnetic property was observed for synthesized ZnFe2O4/ZnO nanoparticles using vibrating sample magnetometer (VSM). The methylene blue and methyl orange were taken as model dyes to illustrate the photocatalytic activity of synthesized products under visible light irradiation. Maximum degradation of 99% for methyl orange (MO) was achieved by the use of 13 nm sized ZnFe2O4/ZnO nanoparticles as catalyst and a minutely less activity was observed for the methylene blue (MB) degradation (98%), when the photocatalytic processes were carried out for 5 h and 6 h, respectively.